Sandipan Das has uploaded this change for review. (
https://gem5-review.googlesource.com/c/public/gem5/+/16626
Change subject: arch-power: Add fixed-point compare instructions
......................................................................
arch-power: Add fixed-point compare instructions
This adds the following compare instructions:
* Compare Ranged Byte (cmprb)
* Compare Equal Byte (cmpeqb)
Change-Id: I44765b3a9a8f0a3d81ecd6984efce3fd01ba4b24
Signed-off-by: Sandipan Das <[email protected]>
---
M src/arch/power/isa/decoder.isa
M src/arch/power/isa/formats/integer.isa
2 files changed, 25 insertions(+), 1 deletion(-)
diff --git a/src/arch/power/isa/decoder.isa b/src/arch/power/isa/decoder.isa
index 1838637..943d17d 100644
--- a/src/arch/power/isa/decoder.isa
+++ b/src/arch/power/isa/decoder.isa
@@ -476,6 +476,30 @@
cr = makeCRField((uint32_t)Ra, (uint32_t)Rb, xer.so);
}
}});
+
+ 192: cmprb({{
+ uint32_t src1 = Ra_ub;
+ uint32_t src2 = Rb_uw;
+ uint8_t src2lo = src2 & 0xff;
+ uint8_t src2hi = (src2 >>= 8) & 0xff;
+ uint32_t res = (src2lo <= src1) & (src1 <= src2hi);
+ if (length) {
+ src2lo = (src2 >>= 8) & 0xff;
+ src2hi = (src2 >>= 8) & 0xff;
+ res = ((src2lo <= src1) & (src1 <= src2hi)) | res;
+ }
+ cr = res << 2;
+ }});
+
+ 224: cmpeqb({{
+ // Based on "Determine if a word has a byte equal to n"
+ // from
https://graphics.stanford.edu/~seander/bithacks.html
+ const uint64_t m1 = 0x0101010101010101;
+ const uint64_t m2 = 0x8080808080808080;
+ uint64_t res = Rb ^ (Ra_ub * m1);
+ res = (res - m1) & ~res & m2;
+ cr = (res != 0) << 2;
+ }});
}
// Integer logic instructions use source registers Rs and Rb,
diff --git a/src/arch/power/isa/formats/integer.isa
b/src/arch/power/isa/formats/integer.isa
index e5e6d2d..41fe64c 100644
--- a/src/arch/power/isa/formats/integer.isa
+++ b/src/arch/power/isa/formats/integer.isa
@@ -67,7 +67,7 @@
let {{
-readXERCode = 'Xer xer = XER;'
+readXERCode = 'Xer xer M5_VAR_USED = XER;'
setXERCode = 'XER = xer;'
--
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Gerrit-Project: public/gem5
Gerrit-Branch: master
Gerrit-Change-Id: I44765b3a9a8f0a3d81ecd6984efce3fd01ba4b24
Gerrit-Change-Number: 16626
Gerrit-PatchSet: 1
Gerrit-Owner: Sandipan Das <[email protected]>
Gerrit-MessageType: newchange
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